Glass, CR-39, polycarbonate, Trivex and high index - take your choice

摘要

After a recent visit to Asia several truths became self-evident. Glass or mineral lenses are very rapidly disappearing from the marketplace. CR-39 plastic (organic) lenses are replacing glass even in agrarian, rural environments. This appears to reinforce the theory of 'technological substitution' that one material will replace another when it exhibits superior characteristics. The marketplace will determine these factors and in the case of glass lenses versus plastic, it has. In spite of glass's optical superiority, stability, and scratch resistance, plastic has taken over the market. What appeared to be a close contest, with glass and plastic splitting the market evenly or on a 60/40 basis for some years, has changed. Glass is now a minor segment of the market as some of the last holdouts such as the German market slowly disappear. It is surprising that plastic lenses, although originally popularised in the United States with its drop ball test and product liability concerns, have taken over worldwide. An indication that the market is more interested in weight of material, ease of manufacture and economic add-ons. The word eyeglass is fast becoming an oxymoron.